Will this external pump set-up work?

[islandguy11]

As per original plans in near future I'm going to add a UV sterilizer to my 325 Arowana tank which was set up last December. Need your opinions on one approach I'm thinking about to do this.

-- As you can see in pic below on the right side I have a 2000 L/hr internal pump feeding the OH shower filter. This pump is not powerful enough to feed both a UV sterilizer and the OHF.
-- I have an un-opened Jebao DCT-8000 pump (probably a bit more powerful than I need but I can dial it down to about 5,000 L/hr from the get-go using the controller, then head pressure will help after that), sitting on the shelf and would like to use this.
-- But for aesthetic and other reasons (vibration/another thing for Aro to hit or bite), I'd prefer not to put this pretty good-sized pump inside the tank unless no other choice.
-- As a side note I don't want to run a sump at this time for several reasons.

So here's my question: can I put the DCT-8000 in say a decent sized tote or even plastic trash bin filled with water just behind the tank, then hard-plumb both intake and return lines? So essentially the tote or trash bin would simply act as a reservoir for the pump to keep it from overheating (and out of sight). With the return line I would use a T-splitter, one side going to OHF and the other to UV sterilizer (and from there back into the tank). Each side line off the T-splitter would have a ball valve to control and balance the flow rate as needed, esp. to get proper UV sterilization.

I can guess the main issue would be how much the pump raised the water temperature in the tote/bin. The DCT-8000 is max 67.6 watts but I would likely have that dialed down closer to about 40 watts, so we're not talking huge power/heat). Was thinking I could easily add a big air stone from my DC air pump, which has plenty of unused pressure, to help at least somewhat to reduce water temp in the tote/bin. I also don't mind topping it off with a jug or two of water every few days to help with evaporation.

Plz let me know if you think this would work OK, or if you see some potential issue(s) I'm missing and better to just put the DC pump inside the tank.

 

[BichirKing]

how about swapping the pump you have in there now with the DCT use a t and ball valves to regulate flow to the filter and the uv?

 

[islandguy11]

how about swapping the pump you have in there now with the DCT use a t and ball valves to regulate flow to the filter and the uv?

Well either way the pump currently in the tank is coming out. And yes I could put the DCT inside the tank, but for reasons mentioned above (aesthetics, another thing for Aro to hit/bite, vibrations), I'd prefer for there to be no pump inside the tank at all, hence the idea to put it in the external reservoir (and again I don't want to go the route of putting in a full-on sump and hob overflow system).

 

[BichirKing]

only problem with the external reservoir like you propose is pumps are not good at pulling water they're designed to push water. even self priming pumps don't pull water enough to get the water from the tank to the res.

 

[islandguy11]

only problem with the external reservoir like you propose is pumps are not good at pulling water they're designed to push water. even self priming pumps don't pull water enough to get the water from the tank to the res.

Thx for input, that's a good point I hadn't considered. In that case I guess I'll get a bit smaller of a DC pump, maybe a DCP-6000 and put that in the tank.

 

[islandguy11]

only problem with the external reservoir like you propose is pumps are not good at pulling water they're designed to push water. even self priming pumps don't pull water enough to get the water from the tank to the res.

Question: from what I understand most canister filter pumps also are designed more for pushing than pulling water, hence why many put them under their tanks and then gravity feeds the input. Once an external pump like I'm thinking about was primed, if it were located under the tank or near the floor wouldn't gravity have a similar effect on the input side after a siphon flow was established?

 

[duanes]

One thing about UV sterilizers, is the slower the flow thru them, the better they work, because it is the detention time in front of the UV bulb destroys the target organisms. If flow is too strong, an quick, and detention time limited, they become impotent, so splitting the flow with a slow flow thru the UV pipe may leave plenty of head room for other side.

 

[islandguy11]

One thing about UV sterilizers, is the slower the flow thru them, the better they work, because it is the detention time in front of the UV bulb destroys the target organisms. If flow is too strong, an quick, and detention time limited, they become impotent, so splitting the flow with a slow flow thru the UV pipe may leave plenty of head room for other side.

Thx for input Duanes, yeah that's my intention with the t-split and ball valve there so I can control that all-important UV flow rate. For determining proper flow rate to hopefully achieve Level 2 Sterilization/pathogenic control, I use a chart you might have seen at http://www.americanaquariumproducts.com/AquariumUVSterilization.html (it's "proprietary information" as they clearly state so I haven't copy and pasted the chart here, it's about half way down that very long page). If you or anyone else has other resources in this regard would love to see them (as I'm basically following AA's chart on blind faith they know what they're talking about).

While on the topic of UV sterilizers, I'm wondering if a 55 watt unit would be large enough for a 325g?

Also do you think my pump in external reservoir idea will work, or just better to stick the pump in the tank?

 

[jaws7777]

No experience with uv but one thing to consider with the external bin would be to get the water level low enough to account for any back flow when you shut the system off or lose power

 

[islandguy11]

No experience with uv but one thing to consider with the external bin would be to get the water level low enough to account for any back flow when you shut the system off or lose power

Actually I was thinking to hard plumb both the intake and the outlet of the pump, so the water level in the bin shouldn't be affected (except through evaporation) -- the pump would be getting all of its water from the tank and putting it back into the tank (after UV and OHF) -- the reservoir would only act as kind of a heat reducer (and way to hide the pump).